//类的可见性
//父类
class Animal {
  private __run__() {
    console.log('Animal内部辅助函数')
  }

  protected move() {
    this.__run__()
    console.log("走两步")
  }

  public run() {
    this.__run__()
    this.move()
    console.log("跑起来")
  }
}

//子类
class Dog extends Animal {
  bark() {
    console.log("汪汪")
  }
}

let d = new Dog();
d.run()